U.S. patent application number 12/314006 was filed with the patent office on 2010-06-03 for power system.
This patent application is currently assigned to Caterpillar Inc.. Invention is credited to Brett Bailey, Clifford Eugene Cotton, III, Christopher Joseph Rynders, JR., Matthew Owen Stefanick.
Application Number | 20100132341 12/314006 |
Document ID | / |
Family ID | 42221552 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100132341 |
Kind Code |
A1 |
Stefanick; Matthew Owen ; et
al. |
June 3, 2010 |
Power system
Abstract
The present disclose is directed to a power system. The power
system may include a power source that creates a flow of exhaust.
The power system may further include a particulate collection
device that receives the flow of exhaust. The power system may also
include an additive injector located downstream of the power
source, the additive injector may be configured to provide a
controlled supply of additive to the flow of exhaust.
Inventors: |
Stefanick; Matthew Owen;
(Peoria, IL) ; Bailey; Brett; (Peoria, IL)
; Rynders, JR.; Christopher Joseph; (Peoria Heights,
IL) ; Cotton, III; Clifford Eugene; (Bradford,
IL) |
Correspondence
Address: |
CATERPILLAR/FINNEGAN, HENDERSON, L.L.P.
901 New York Avenue, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Caterpillar Inc.
|
Family ID: |
42221552 |
Appl. No.: |
12/314006 |
Filed: |
December 2, 2008 |
Current U.S.
Class: |
60/295 ; 29/428;
60/274; 60/297 |
Current CPC
Class: |
F01N 3/029 20130101;
F01N 2560/08 20130101; F01N 3/206 20130101; F01N 2610/10 20130101;
F01N 9/002 20130101; F01N 2610/01 20130101; Y02T 10/47 20130101;
F01N 2510/065 20130101; F01N 2610/146 20130101; F01N 2560/06
20130101; Y02T 10/40 20130101; F01N 3/0293 20130101; Y10T 29/49826
20150115; F01N 3/0296 20130101 |
Class at
Publication: |
60/295 ; 60/297;
29/428; 60/274 |
International
Class: |
F01N 3/023 20060101
F01N003/023; F01N 3/021 20060101 F01N003/021 |
Claims
1. A power system, comprising: a power source that creates a flow
of exhaust; a particulate collection device that receives the flow
of exhaust; and an additive injector located downstream of the
power source, the additive injector configured to provide an
additive to the flow of exhaust; wherein the additive includes a
metal-based additive.
2. The power system of claim 1, wherein the additive injector is
coupled to a passageway which houses the particulate collection
device, and wherein the additive injector is located upstream of
the particulate collection device.
3. The power system of claim 2, wherein the additive injector is
located downstream of an exhaust manifold of the power source.
4. The power system of claim 1, further including: an additive
tank; and a pump configured to draw the additive from the additive
tank and direct the additive to the additive injector.
5. The power system of claim 1, wherein the metal-based additive is
an iron additive.
6. The power system of claim 1, further including at least one
sensor in fluid communication with the flow of exhaust configured
to sense a parameter of the flow of exhaust.
7. The power system of claim 6, wherein the additive injector is
configured to provide the additive based on the sensed
parameter.
8. A method of assisting regeneration of a particulate collection
device that receives a flow of exhaust from an internal combustion
engine, comprising: supplying an additive to the flow of exhaust
from a location downstream of an exhaust manifold of the internal
combustion engine; and regenerating the particulate collection
device after the additive has been supplied to the flow of
exhaust.
9. The method of claim 8, further including controlling the
supplying of the additive based on a sensed parameter.
10. The method of claim 9, wherein the sensed parameter is
indicative of at least one of a load on the particulate collection
device or a temperature of the flow of exhaust.
11. The method of claim 8, further including controlling a heating
device as a function of an amount of the additive coating the
particulate collection device.
12. The method of claim 8, further including controlling a heating
device when the additive is supplied to the flow of exhaust.
13. The method of claim 8, wherein supplying the additive to the
flow of exhaust includes supplying an additive having at least one
of platinum, copper, cerium, manganese, or iron.
14. The method of claim 13, further including at least partially
coating the particulate collection device with the additive to
oxidize trapped particulate matter in the particulate collection
device.
15. A power system, comprising: a power source that creates a flow
of exhaust; a particulate collection device that receives the flow
of exhaust; an additive injector located downstream of the power
source and upstream of the particulate collection device; at least
one sensor configured to sense a parameter of the flow of exhaust
and generate a signal corresponding to the parameter; and a
controller in communication with the additive injector and the at
least one sensor, the controller being configured to control
operation of the additive injector in response to the signal.
16. The power system of claim 15, wherein the additive injector is
configured to inject an additive to the flow of exhaust, wherein
injections of the additive facilitate regeneration of the
particulate collection device.
17. The power system of claim 16, wherein the additive includes a
metal-based additive.
18. The power system of claim 15, wherein the additive injector is
located downstream of an exhaust manifold associated with the power
source.
19. The power system of claim 15, wherein the at least one sensor
is a load sensing device.
20. A method of assembling an additive injector to an
after-treatment system of a power system, comprising: coupling the
additive injector to a supply of additive; coupling the additive
injector to a passageway of the after-treatment system; and
connecting the additive injector to a controller associated with
the power system, wherein connecting includes supplying the
controller with software to control the additive injector to
regulate the supply of additive delivered from the additive
injector to the passageway.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to a power system
and, more particularly, to a power system having an additive
injector located downstream of a power source to provide a
controlled supply of additive to the flow of exhaust.
BACKGROUND
[0002] Internal combustion engines, including diesel engines,
exhaust a complex mixture of potential air pollutants. These air
pollutants may include solid material known as particulate matter
or soot. Due to increased environmental concern, diesel engine
exhaust emission standards have become increasingly stringent. The
amount of particulate matter emitted from an engine may be
regulated depending on the type of engine, size of engine, and/or
class of engine.
[0003] One method implemented by engine manufacturers to comply
with the regulation of particulate matter exhausted to the
environment has been to remove the particulate matter from the
exhaust flow of an engine using a device called a particulate trap
or diesel particulate filter (DPF). A DPF is a filter designed to
trap particulate matter in, for example, a wire mesh or ceramic
honeycomb filtering media. Over time the particulate matter may
accumulate in the filtering media, thereby reducing filter
functionality and engine performance.
[0004] Various regeneration techniques may be employed to manage
the accumulated particulate matter. For example, U.S. Pat. No.
6,488,725 ("the '725 patent") issued to Vincent et al. on Dec. 3,
2002, describes a method of supplying an iron-containing fuel
soluble additive for use in the regeneration of a particulate
filter trap. The method includes supplying an additive to the fuel
prior to combustion. In particular, the supply of additive is added
into the fuel supply chain or is added via a dosing device on-board
the vehicle to either the fuel tank, combustion chamber, or the
inlet system. The additive mixes with the fuel, and the mixture is
combusted to provide a flow of exhaust containing soot particulates
and additives. In operation, the additives reduce the soot
particulate ignition temperature. In this manner, the additives
reduce the energy input required to initiate regeneration of the
particulate filter.
[0005] Although the method described in the '725 patent may
suitably regenerate the particulate filter trap, it may be
problematic. In particular, as the additives travel through the
fuel injectors of the engine, the additives may build-up in the
injector tip. This may reduce the volumetric efficiency and spray
pattern of the injectors. Furthermore, the additives may form a
sediment in the combustion chamber of the engine thereby negatively
affecting engine performance.
[0006] The system of the present disclosure solves one or more of
the shortcomings set forth above and/or other shortcomings in the
art.
SUMMARY
[0007] One aspect of the present disclosure is directed to a power
system. The power system may include a power source that creates a
flow of exhaust. The power system may further include a particulate
collection device that receives the flow of exhaust. The power
system may also include an additive injector located downstream of
the power source, the additive injector may be configured to
provide a controlled supply of additive to the flow of exhaust.
[0008] Another aspect of the present disclosure is directed to a
method of assisting regeneration of a particulate collection device
that receives a flow of exhaust from an internal combustion engine.
The method may include supplying an additive to the flow of exhaust
from a location downstream of an exhaust manifold of the internal
combustion engine. The method may further include regenerating the
particulate collection device after the additive has been supplied
to the particulate collection device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic and diagrammatic illustration of an
exemplary disclosed power system including an after-treatment
system; and
[0010] FIG. 2 is a flowchart depicting an exemplary disclosed
operation of the after-treatment system of FIG. 1.
DETAILED DESCRIPTION
[0011] FIG. 1 illustrates a power system 10 including a power
source 12 and an after-treatment system 16. In one embodiment,
power system 10 may be associated with a mobile vehicle such as a
passenger vehicle, a vocational vehicle, a farming machine, a
mining machine, or a construction machine. Alternatively, power
system 10 may be associated with a stationary machine such as, for
example, a power generation machine.
[0012] For the purposes of this disclosure, power source 12 is
depicted and described as a four-stroke diesel engine. One skilled
in the art will recognize, however, that power source 12 may be any
other type of internal combustion engine such as, for example, a
gaseous fuel-power engine (e.g., a natural gas engine), or any
other type of combustion engine known to one skilled in the art.
Power source 12 may include an engine block that at least partially
defines a plurality of combustion chambers 14. In the illustrated
embodiment, power source 12 includes four combustion chambers. It
is contemplated, however, that power source 12 may include a
greater or lesser number of combustion chambers and that the
combustion chambers may be disposed in an "in-line" configuration,
or a "V" configuration, or any other suitable configuration.
[0013] Power source 12 may draw an air/fuel mixture into each
combustion chamber 14 to produce a combustion of power, heat, and
exhaust. In particular, power source 12 may include an intake
manifold 18 to supply the air/fuel mixture to power source 12.
Intake manifold 18 may receive fuel from a fuel supply (not shown)
and air from an air supply (not shown). Power source 12 may further
include an exhaust manifold 20 having exhaust passageways, each
passageway being in fluid communication with one of combustion
chambers 14 of power source 12. Exhaust manifold 20 may expel
exhaust flow away from power source 12 towards after-treatment
system 16 located downstream of power source 12.
[0014] After-treatment system 16 may reduce emissions of harmful
gasses and particulate matter emitted from power source 12 after a
combustion process. After-treatment system 16 may include a
passageway 24, which may be in fluid communication with exhaust
manifold 20 of power source 12. After-treatment system 16 may also
include a particulate collection device 26 and a heating device 28.
After-treatment system 16 may further include devices that provide
a supply of additive solution to the flow of exhaust from power
source 12 to facilitate regeneration of particulate collection
device 26. Specifically, after-treatment system 16 may include an
additive tank 30, a pump 32, an additive injector 34, and a control
system 36. It is contemplated that after-treatment system 16 may
include other components such as, for example, a selective
catalytic reductant device, a NOx trap, and/or any other
after-treatment system component known in the art.
[0015] Particulate collection device 26 may be disposed at least
partially across the cylindrical width (i.e., cross-section) of
passageway 24 and either removably or fixedly secured at its
perimeter to passageway 24. Particulate collection device 26 may be
any variety of diesel particulate filter ("DPF") such as, for
example, a sintered metal fiber flow-through filter, cordierite or
silicon carbide wall-flow filter, partial filter, or any other DPF
known in the art. Particulate collection device 26 may be
configured to trap particulate matter within a wire mesh or ceramic
honeycomb filtration medium. As the flow of the exhaust passes
through the filtration medium, particulate matter, for example,
unburned hydrocarbons, may impinge against and be blocked by the
filtration medium. Over time, the particulate matter may build up
within particulate collection device 26 and the filtration medium
may become saturated. If unaccounted for, this build up of
particulate matter could reduce the flow of exhaust through the
filtration medium and negatively effect engine performance.
[0016] Heating device 28 may be associated with particulate
collection device 26 to selectively promote regeneration of
particulate collection device 26. For example, heating device 28
may be integrated with or adjacent to particulate collection device
26. Heating device 28 may embody, for example, an electric grid. It
is contemplated that heating device 28 may alternatively embody a
fuel-fired burner or a fuel control strategy that selectively heats
the flow of exhaust, if desired.
[0017] Additive tank 30 may constitute a reservoir configured to
hold a supply of additive. Additive tank 30 may store diesel fuel
and additive in an amount in the range of from about 1% to 50% by
weight of the diesel fuel additive mixture. It is contemplated,
that the additive may be alternatively stored in a lower boiling
point hydrocarbon. The additive may include, for example, iron,
barium, calcium, cerium, manganese, platinum, and/or any other
transition metal configured to catalyze the oxidation of
particulate matter.
[0018] Pump 32 may direct the supply of additive from additive tank
30 to additive injector 34. Pump 32 may be any kind of
high-precision, metered, low-flow rate pump. Pump 32 may be a
diaphragm pump or any other pump known to one skilled in the
art.
[0019] Additive injector 34 may be any appropriate type of fluid
injector configured to inject an amount of additive into passageway
24 of after-treatment system 16. As illustrated in FIG. 1, additive
injector 34 may be located downstream of power source 12 and
upstream of particulate collection device 26. In particular,
additive injector 34 may be mounted at any point along the length
of passageway 24 between exhaust manifold 20 of power source 12 and
particulate collection device 26 given that the supply of additive
delivered to the flow of exhaust does not enter combustion chamber
14 of power source 12. Additive injector 34 may be mounted to
passageway 24 such that the nozzle of the injector is in fluid
communication with the flow of exhaust therein. It is contemplated
that additive injector 34 may be mechanically, hydraulically, or
electrically actuated.
[0020] Control system 36 may be associated with after-treatment
system 16 and may include components configured to regulate the
operation of additive injector 34 in order to facilitate
regeneration of particulate collection device 26. In particular,
control system 36 may include a particulate collection device load
sensor device including a first pressure sensor 40 and a second
pressure sensor 42 configured to generate signals indicative of the
load on the particulate collection device 26; a temperature sensor
48 configured to generate a signal indicative of the temperature of
the flow of exhaust; and a controller 38 in communication with
first pressure sensor 40, second pressure sensor 42, and
temperature sensor 48. Controller 38 may be configured to regulate
the operation of additive injector 34 in response to input received
from first pressure sensor 40, second pressure sensor 42, and
temperature sensor 48. Controller 38 may be additionally configured
to control the operation of heating device 28.
[0021] First pressure sensor 40 and second pressure sensor 42 may
be associated with passageway 24 of after-treatment system 16 and
in communication with controller 38 via communication lines 44. In
particular, first pressure sensor 40 may be operable to generate a
signal indicative of a pressure of the flow of exhaust at or
upstream of particulate collection device 26 but downstream of
power source 12. Second pressure sensor 42 may be operable to
generate a signal indicative of a pressure of the flow of exhaust
downstream of particulate collection device 26. First and second
pressure sensors 40, 42 may be capable of detecting a pressure
differential across particulate collection device 26, wherein the
pressure differential may be indicative of the amount of
particulate matter contained within particulate collection device
26. It is contemplated that first and second pressure sensors 40,
42 may alternatively and/or additionally be any type of sensor
capable of directly detecting the quantity of particulate matter
within particulate collection device 26. For example, it is
contemplated that the particulate matter load sensing device may be
a single sensor such as, for example, a mass sensor.
[0022] Temperature sensor 48 may be associated with passageway 24
of after-treatment system 16 upstream from particulate collection
device 26 and in communication with controller 38 via communication
line 46. Specifically, temperature sensor 48 may be mounted to
passageway 24 such that the temperature sensor 48 may measure a
temperature of the exhaust flow therein. Alternatively, temperature
sensor 48 may measure a temperature of particulate collection
device 26 and/or a temperature of the captured particulates. That
is, temperature sensor 48 may be thermally coupled with the
particulate collection device 26 so as to determine its
temperature. Temperature sensor 48 may also be located downstream
of particulate collection device 26, if desired. Temperature sensor
48 may be operable to generate a signal indicative of the
temperature of exhaust flow and/or particulate matter trapped
within particulate collection device 26.
[0023] Additionally and/or alternatively, the temperature of the
flow of exhaust and/or the pressure differential across particulate
collection device 26 may be estimated by controller 38 rather than
measured by sensors 40, 42, and 48. That is, controller 38 may
determine the temperature and pressure difference across
particulate collection device 26 as a function of variables related
to one or more known operating conditions of power source 12 and/or
the machine associated therewith (i.e., virtual sensors). For
example, one or more engine performance maps relating a fueling
amount, ignition timing, power output, engine speed, boost
pressure, engine temperature, an air/fuel ratio, and/or other known
parameters may be stored within the memory of controller 38. Each
of these maps may be in the form of tables graphs and/or equations
and include a compilation of data collected from lab and/or field
operation of power source 12. Controller 38 may receive data
relating to the operation of the power system 10 and may reference
one or more of these maps in order to estimate a temperature
associated with particulate collection device 26 and/or pressure
difference across particulate collection device 26 for a given
operating condition of power source 12. In this manner, controller
38 may measure or estimate pressure and/or temperature data from
which decisions about additive injection may be made.
[0024] Controller 38 may embody a single microprocessor or multiple
microprocessors that may control the operation of after-treatment
system 16. Numerous commercially available microprocessors can be
configured to perform the functions of controller 38. It should be
appreciated that controller 38 could readily embody a general
machine microprocessor capable of controlling numerous machine
functions, an engine microprocessor, or a transmission
microprocessor. Controller 38 may include a memory, a secondary
storage device, a processor, software, and any other components for
running an application. Various other circuits may be associated
with controller 38, such as power supply circuitry, signal
conditioning circuitry, solenoid driver circuitry, and other types
of circuitry.
[0025] Controller 38 may regulate the supply of additive delivered
by additive injector 34 to passageway 24 in order to facilitate
regeneration of particulate collection device 26. Controller 38 may
regulate the amount of additive by sending a command signal via
communication line 50 to an actuator such as, for example, a
solenoid actuator of additive injector 34. When active regeneration
is required, controller 38 may send a command signal via
communication line 52 to heating device 28 to heat particulate
collection device 26.
[0026] FIG. 2 illustrates an exemplary method according to one
embodiment of the present disclosure. FIG. 2 will be discussed in
more detail in the following section to further illustrate the
disclosed system.
INDUSTRIAL APPLICABILITY
[0027] The disclosed system may be applicable to any power system
having an after-treatment system that provides for regeneration of
a particulate collection device. For example, the disclosed
after-treatment system 16 may be applicable to mobile systems, such
as engines that power mobile vehicles (e.g., automobiles,
semi-trailer trucks, construction equipment, marine vessels, etc.).
The after-treatment system 16 may also be applicable to stationary
machines, such as electric power generation sets. The operation of
power source 12 and after-treatment system 16 will now be
explained.
[0028] Referring to FIG. 1, power source 12 may receive an air/fuel
mixture from intake manifold 18, combust the mixture in combustion
chambers 14, and output a flow of exhaust through exhaust manifold
20 of power source 12 to after-treatment system 16. The flow of
exhaust may contain a complex mixture of air pollutants, which can
include particulate matter such as soot. The release of particulate
matter into the environment may be minimized by passing the flow of
exhaust through particulate collection device 26 of after-treatment
system 16. As this particulate matter laden flow of exhaust is
directed from power source 12 through particulate collection device
26, particulate matter may build up in the device 26 thereby
adversely affecting engine performance.
[0029] In order to facilitate regeneration of the particulate
collection device 26, a supply of additive may be delivered from
additive injector 34 to passageway 24 of after-treatment system 16
downstream of power source 12 and upstream of particulate
collection device 26. The supply of additive may include, for
example, iron, platinum, copper, cerium, manganese, barium,
calcium, and/or any other transition metal configured to catalyze
the oxidation of particulate matter. In passageway 24, these
metal-based fuel additives may mix with the flow of exhaust and
flow downstream to particulate collection device 26 where the
additives may coat portions of the particulate collection device
26. At particulate collection device 26, the additives may undergo
a chemical reaction which may catalyze soot oxidation. That is, the
oxidizing metals of the metal-based fuel additives may lower the
combustion threshold temperature of the soot thereby facilitating
regeneration of the particulate collection device 26.
[0030] Turning now to FIG. 2, during operation of power system 10,
controller 38 may monitor the load within particulate collection
device 26 by the load sensing device of first and second sensors
40, 42 (step 70). While monitoring the load, controller 38 may
additionally monitor the temperature of the flow of exhaust exiting
power system 10 by temperature sensor 48.
[0031] When the temperature of the flow of exhaust is within the
activation range (e.g., 200.degree. C.-500.degree. C.) of
particulate collection device 26 (Step 80), controller 38 may
calculate the ratio of particulate matter within particulate
collection device 26 to additive coated on particulate collection
device 26. Controller 38 may derive the amount of additive coated
on particulate collection device 26 based on the number of previous
additive injections. Controller 38 may reference one or more maps
to determine if the particulate matter-to-additive ratio is
acceptable (i.e., sufficient to facilitate regeneration of
particulate collection device 26) (Step 90). When the ratio is
acceptable, controller 38 may send a command signal, via
communication line 50, to additive injector 34 instructing additive
injector 34 to provide a supply of additive to the flow of exhaust
in passageway 24 of after-treatment system 16 (Step 100) so as to
maintain the particulate matter-to-additive ratio. When the ratio
is not acceptable, controller 38 may reference one or more maps to
determine the appropriate amount of additive to supply to the flow
of exhaust. Controller 38 may send a command signal to additive
injector 34 to adjust the supply of additive accordingly (Step
110).
[0032] While supplying additive to the flow of exhaust, controller
38 may continue to monitor the load on particulate collection
device 26 and determine if regeneration is required (Step 120). In
particular, controller 38 may reference one or more stored maps to
determine when the amount of particulate matter within particulate
collection device 26 is above or below a particulate matter load
threshold value. When controller 38 determines that the amount of
particulate matter is above a particulate matter load threshold
value, controller 38 may classify that particulate collection
device 26 is in need of regeneration. In contrast, when the amount
of particulate matter within particulate collection device 26 is
below a particulate matter load threshold value, controller 38 may
classify that particulate collection device 26 is not in need of
regeneration. It is contemplated that the particulate matter load
threshold value may vary dependent on characteristics of power
source 12 and after-treatment system 16. For example, the
particulate matter load threshold value may vary dependent on
engine size, power level, or any other characteristic that may
affect the need to regenerate particulate collection device 26.
[0033] When particulate collection device 26 is in need of
regeneration, controller 38 may reference one or more maps to
determine if the flow of exhaust is above the first threshold value
(e.g., 200.degree. C.) (Step 130). If the temperature of the flow
of exhaust is above the first threshold value, then passive
regeneration may be sufficient to regenerate particulate collection
device 26 (Step 140). In contrast, if the temperature of the flow
of exhaust is not above the first threshold value, active
regeneration may be required. Controller 38 may then determine if
the amount of additive coating the particulate collection 26 device
is sufficient for active regeneration (Step 150). When the amount
of additive is sufficient, controller 38 may control heating device
28 (Step 160) to burn away the collected particulate matter. If,
however, the amount of additive is insufficient for a complete
burn, controller 38 may reference one or more maps to determine the
appropriate amount of additive, and may send a command signal to
additive injector 34 to adjust the supply of additive accordingly
(Step 110).
[0034] Based on the above-disclosed system, the location of the
disclosed additive injector 34 may help ensure that the additive
does not enter the combustion chamber 14 of power source 12. In
this manner, the disclosed additive injector 34 may avoid problems
associated with the supply of additives travelling through power
source 12. In addition, because the supply of additive is delivered
into the flow of exhaust as a function of the load on particulate
collection device 26 and the temperature of the flow of exhaust,
controller 38 may regulate the timing and amount of additive
supplied to the particulate collection device 26.
[0035] It will be apparent to those skilled in the art that various
modifications and variations can be made to the system of the
present disclosure without departing from the scope of the
disclosure. Other embodiments will be apparent to those skilled in
the art from consideration of the specification and practice of the
system disclosed herein. It is intended that the specification and
examples be considered as exemplary only, with a true scope of the
disclosure being indicated by the following claims and their
equivalents.
* * * * *